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Capturing System Voltage

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Kf7vol's picture
Capturing System Voltage

Good Morning Group,

I have deployed a node at a remote site and am looking to see what my options are for capturing voltage. At this time I only have one radio on location. It is on 2 batteries with no way to generate power at this time. Is there something in a ubiquity nano that will allow you to look at system voltage in the command line? I know secondary systems like a Pi or Arduino can do it as well but I am trying to limit my power consumption with extra devices.

Thanks in advance!



The Nano doesn't. Almost all of the MikroTik devices have the capability in hardware, but as far as I know it's not implemented in the AREDN code. Not sure about the underlying OpenWRT, if it's there or not? Maybe our developers would know?

I use MikroTik hEX PoE routers as switches at my sites. It provides voltage as well as individual current monitoring and on/off control for the PoE ports. The switch will run at 12 or 24 and pass that voltage to the PoE ports, but keep in mind cable distances to the radios at 12V are limited to under ~50ft due to voltage drop. However since I convert 12 to 24 volts I only see the output of the converter not the battery voltage. If your system is 24V or you have super short 12V runs, you'd be good to go. At some point, you'll need a switch anyways!

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Kf7vol's picture
Does anyone know the power

Does anyone know the power draw of a switch like this or would there be another device that could do the same on less power?


A spare MikroTik hEX PoE Lite here tests 69mA at 13.8V with nothing plugged in and 82mA with one port active (a laptop). Replacing the laptop with a Nano M5 set to full power, the switch + node is ~235mA +/-20, it jumps around a bit.

Note that I started to test at 12.6V, a typical battery voltage, but the Nano wasn't stable. The switch reports 12.0V so there's a diode/tranny drop in it probably the switching for PoE control. One more reason to stay at 24V nominal.

The Lite is the 10/100-only version of the gigabit hEX PoE.

Kf7vol's picture
Thank you!

Thank you!

I will take this back to our team..

K6CCC's picture
Can you verify if the hEX

Can you verify if the hEX Lite shows the voltage.  I just checked my two Mikrotik routers that are in use.
Router 1 = RB750Gr3 (hEX) ROS version 6.46.4 - Does display system voltage and temperature
Router 2 - RB750r2 (hEX Lite) ROS version 6.46.4 - Does NOT display temp or voltage
Neither of mine are the POE version as I have no need for that.
I also noted that the voltage displayed is lower than actual.


You found one that doesn't have it!

hEX Lite (non-PoE verison) doesn't show on either Winbox or command line (/system health print).

K9CQB's picture
I'd love to have this voltage monitoring for my solar nodes.

For my solar powered nodes, I chose to run MikroTik devices because they can often handle lower voltages when the power dips down in the dead of winter. Therefore, I would love to see the ability to monitor input voltage on the AREDN firmware, if only with the MikroTik devices. Heck, I'll take what I can get.

-Damon K9CQB 

VA7NIC's picture
Remote site voltage monitoring

We have gone the route of using network enabled Arduinos to monitor and report remote site voltage and current levels directly using the arduino i/o, and another site has an Arduino that can speak modbus to one of our Morningstar solar charge controllers.

From each site, we see almost realtime (within the 5-10 sec polling times) incoming solar voltage and current, battery voltage and current, as well as the external power supply voltage and current.  We can also see if the sites AC power has failed or if someone has opened up a door on the cabinet.

From there, we gather all the data using a Raspberry Pi running Node-Red, and can produce a screen like I will attach below.


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Kf7vol's picture
This is good stuff.

This is good stuff.

Thank you,

VE2DTL's picture
very inteeresting Nick.

Can you share some doc or links?

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